Don't worry, It's a common misconception. I was told the same thing at secondary school, but learnt otherwise later from reading up in depth on the subject. Our education system really needs to sort itself out.

There were numerous reasons for the treaty being signed. The French wanted to ensure Germany never ever became a threat again and thought the original treaty wasn't harsh enough. The British wanted a treaty that would balance the power of Europe and believed the treaty was the best idea. I believe Wilson thought the best solution was a least harsh treaty so long as Germany transitioned towards a full Democracy. And of course the Italians wanted harsher terms overall in order to regain the land they saw as rightfully theres from the Austrian-Hungarians but the Americans would not allow this.

Overall the aim was to neutralise the thought of another European War. But in the process of doing so created the climate for an even bigger war 20 years later, and as we saw a combination of Democracy and hate towards the Entente for what they did gave birth to the Second World War.